US3906243A - Retrofit emergency lighting system - Google Patents

Retrofit emergency lighting system Download PDF

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Publication number
US3906243A
US3906243A US41565373A US3906243A US 3906243 A US3906243 A US 3906243A US 41565373 A US41565373 A US 41565373A US 3906243 A US3906243 A US 3906243A
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US
United States
Prior art keywords
primary winding
lamp
winding
ballast
filament
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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English (en)
Inventor
Rollie R Herzog
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
CONSTRUCTION MATERIALS A DIVISION OF GENERAL ELECTRIC Co
MATERIALS A DIVISION OF GENERA
Original Assignee
MATERIALS A DIVISION OF GENERA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by MATERIALS A DIVISION OF GENERA filed Critical MATERIALS A DIVISION OF GENERA
Priority to US41565373 priority Critical patent/US3906243A/en
Priority to ZA00746374A priority patent/ZA746374B/xx
Priority to GB4885074A priority patent/GB1481345A/en
Priority to DE19742453496 priority patent/DE2453496A1/de
Priority to JP13007074A priority patent/JPS5079974A/ja
Application granted granted Critical
Publication of US3906243A publication Critical patent/US3906243A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
    • H02J9/065—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads for lighting purposes

Definitions

  • bal- [52] U.S. Cl. 307/66; 315/86; 315/105; last t f is an isolation transfomer having the I 7 336/69; 336/160; 336/183 secondary winding connected across the lamp.
  • H02 9/00; H0513 41/ 14 of filament windings are connected to the filaments of [58] Field of Search 317/14, l5, 18 D; the lamp and are positioned laterally with respect to 3115/1316; 7, 861 105; 307/171 661 the primary winding and in a pancake form so as to 157; 336/69, 70, 160, 165, 183 rovide low capacitance between the filament wind- I ings and primary winding.
  • An inverter circuit which is [561 References Cited driven by a DC battery, is further connected across UNITED STATES PATENTS the lamp for operating the lamp during emergency 2,356,558 8/1944 2 Bahring 336/183 conditions-
  • the inverter circuit Operates at Such a 3,( )89,980 5/1963 Neusbaum 315/105 quency soas to minimize capacitive leakage and in- 3,116,437 12/1963 Harvey 317/15 ductive shunt current losses, 3,209,241 9/1965 Book et al 317/14 R 3,596,135 7/1971 Stenger et a1 317/15 1 Claim, 6 Drawing Figures 23 i" ' ⁇ .
  • the present invention relates to a retrofit emergency lighting system including an AC ballast and an inverter for operating at least one gaseous discharge lamp during normal and emergency conditions. More particularly, it relates to a means for providing electrical isolation between the circuit components on the secondary side of the ballast transformer and ground so as to reduce the hazard of electrical shock and further reduce power losses during the normal mode and especially during the emergency mode of operation.
  • Gaseous discharge lamps for example fluorescent lamps, have a negative resistance characteristic. That is, as the current in the lamp begins to rise, the voltage across the lamp begins to fall causing more and more current to be drawn and eventually destroying the lamp.
  • Various types of inductive and capacitive devices have been used to limit this current and thus ballast the lamp. These lamps usually operate from a 60Hz AC power source during the normal mode of operation.
  • emergency lighting systems which utilize inverter circuits driven by a DC battery. The inverter is connected across the lamp and it operates the lamp at a high frequency level, e.g. oKHz. Because ballast and emergency lighting systems are AC devices, there are'current losses because of capacitive leakage current and inductive shunts to ground.
  • the various transformer windings, wires, etc. are connected in a spaced relationship with a part of the ballast case, which is grounded. This spaced relationship forms a capacitance and an alternating current may flow through this capacitance. If the frequency of lamp operation is high, e.g. 6KHz which might occur during the emergency mode, the impedance of this stray capacitance is low resulting in high capacitance leakage currents.
  • Fluorescent lamps, ballasts, and emergency lighting systems may be mountedv in fixtures which are grounded as shown in FIG. 5.
  • the serviceman burns out and must be replaced by a serviceman, there is a possibility that the serviceman could receive an electrical shockbecause of improper electrical isolation in the ballast.
  • the Serviceman should happen to touch the fixture I of FIG. 5, which is grounded as indicated by ground symbol 2, and at the same time touch either terminal 3 or 4 of fluorescent lamp 5 while theother terminal remains connected in the fixture, he could receive an electrical shock because of this poor isolation. This could happen during either the normal mode of operation or the emergency mode of operation. Because of the relatively low impedance of the stray capacitance at high frequencies, the possibility of electrical shock is greater during the emergency mode.
  • the inverter is used to instant start the lamp at a relatively high voltage (700 volts peak for a 40 watt fluorescent lamp), whereas during the normal 6OH2 mode the lamp is rapid started at a relatively low voltage-(3OO volts peak).
  • interrupt lampholders of a type well known in the art, to be connected to the terminals of the fluorescent lamp. These interrupt lampholders are useful in that the primary or sec ondary circuit of the ballast may be-opened when the fluorescent lamp is to be replaced.
  • interrupt lampholders are sometimes unreliable and are an added cost to a retrofit system. It is, therefore, desirable to lessen the hazard of electrical shock which may occur especially while the high frequency inverter is in operation and the lamp is operated in the emergency mode without using interrupt lampholders.
  • one of the objects of this invention is to provide an improved retrofit ballast and emergency lighting system for operating at least one gaseous discharge lamp.
  • Another object of this invention is to provide a ballast and emergency lighting system for operating at least one gaseous discharge lamp utilizing an inverter which operates at a predetermined frequency which minimizes capacitance leakage currents and inductive current shunts during the emergency mode.
  • Another object is to provide a retrofit ballast and emergency lighting system whereby the electrical shock hazard especially during lamp replacement is substantially lessened.
  • Another object is to provide a ballast and emergency lighting system wherein the capacitance to ground of the ballast is substantially low.
  • Another object is to provide a ballast and emergency lighting system wherein the secondary side of the ballast isolation transformer is substantially isolated from ground.
  • a ballast and an emergency lighting system for operating at least one gaseous discharge lamp including input terminals for connecting the ballast to a source of AC power.
  • a ballasting isolation transformer having primary and secondary windings is further provided. The primary winding is connected across the input terminals and one side of the primary winding is adapted to be connected to ground.
  • the secondary winding is connected across the at least one gaseous discharge lamp.
  • a pair of filament windings are pro vided for preheating the lamp. The filament windings are associated with the primary winding, however, the effective capacitance between the filament and primary windings is substantially low.
  • the emergency lighting system includes a means for operating the lamp at a frequency substantially higher than normal AC in the absence of normal AC power.
  • FIG. 1 is a schematic circuit diagram of an AC ballast for operating the lamp during normal operation and an inverter circuit for operating the. lamp during the emergency mode.
  • FIG. 2 is a portionof a schematic circuit diagram showing a power capacitor which may be included in the circuit of FIG. 1.
  • FIG. 3 is a perspective view of the-capacitor of FIG.
  • FIG...4 is a perspective view of one of the filament windings of FIG. lvconnected to the lamp.
  • FIG. 5 is aside view with one side out away showing a ballast and fluorescent lamp mounted in a fixture.
  • FIG. '6' is aperspective view partially cut away showing the transformer arrangement of the retrofit normal ballast and emergency inverter.:
  • ballastin'g isolationtransformer 8 including main primary winding 9, secondarywinding 10 and core 11 exhibiting rela-' tively high leakage reactance.
  • main primary winding 9 is adaptedto be connected to ground as indicated by symbol 12.
  • Input terminals 6'and 7 are further connected across main primary winding 9 for energizing the'transformer.
  • Secondary winding 10 of ballasting isolation transformer 8 is magnetically coupled to the primary winding 9 but it is not directly electrically coupled to the primary winding as is done in the case of an autotransformer which is the most usual type of transformer ballast.
  • Secondary winding 10 is further connected across gaseous discharge lamp L by its connectionto lamp filaments l3 and 14.
  • the filament windings may be magnetically energized by second primary winding 17, as shown in this embodimennor by the main primary winding 9.
  • the main and second primary and the filament windings maybe mounted on the same core or the second primary and the filament windings may be mounted on a core separate from the mainprimary, as
  • the stray capacitance which is normally associated with the second primary l7 and the filament windings l5 and 16 is made substantially low, that is, the value of stray capacitance, indicated for purposes of explanation at 18 and 19, is relatively low thus substantially isolating the filament windings and the lamp filaments from ground.
  • the means for providing this low stray capacitance will be explained in reference to FIGS. 3 through 6.
  • This particular embodiment includes a-circuit having a 3KHz inverter of a type well known to those skilled in the art, connected across lamp L at points 21 and 22.
  • This inverter circuit 20 may operate at various frequency ranges, however, it has been found that the range which minimizes. both capacitive leakage current and inductive shunt current is between 2.5KHz and 4.0KI-Iz. A frequency much lower than 2.5K Hz will allow substantial shunt current losses through the transformer 8, however, operating at a frequency much higher than 4.0KHz will allow current losses throughthe indicated stray capacitance l8 and 19.
  • the emergency mode circuit further includes capacitors 23 and 24, primary winding25 and secondary winding 26.
  • a description and operation of the emergency mode is more fully explained in an application (Ser. No. 256,252) now US. Pat. No. 3,836,815, invented by Rollie R. Her-20g and assigned to the General Electric Company, assignee of the present invention.
  • FIG.- 2- shows the secondary winding 10 of the transformer 8 included in FIG. 1.
  • Secondary winding 10 has one side connected to power capacitance 27.
  • the use of power capacitance 27 would convert thepurely lagging circuit of FIG. 1 to a partially leading circuit.-If a power capacitance is used its general outer structure may be that which is shown inFIG. 3.
  • FIG. 3 shows a capacitor 27 housed in a can 28 made of metal.
  • an insulation material 29 may be used. This insulation material 29 is shown wrapped around part of the capacitor can 28.
  • the insulation material in this particular embodiment, is polyester, however, other insulation systems may be used having relatively low effective dielectric constant, and being mechanically flexible enough to be wrapped around the capacitor can.
  • FIG. 4 shows filament winding 15 connected to filament 13 of gaseous discharge lamp L. There is a similar filament winding connected to filament 14 but is not shown because-of redundancy.
  • Filament winding 15, in this embodiment, is wound as a narrow pancake type winding. This winding may be only a single. winding turn wide or many turns wide.
  • Insulation partition 39, shown partially cut away, is provided on both sides of the filament winding 15 for electrical insulation. In this embodiment the partitions are made of nylon, however, other materials .with high electrical insulation qualities may be used such as polypropylene.
  • FIG. 6 is a perspective view of the enclosure 35 housing the emergency mode inverter and normal ballast wherein the normal ballast section of the enclosure is cut away.
  • the 3KI-Iz inverter circuit is indicated as inside an enclosed portion 30 and the normal ballast is indicated in the open portion 31.
  • Main primary winding 9 and secondary winding 10 are wound about core 1 l, and are mounted laterally from one another 'and are slightly spaced apart-for electrical isolation.
  • Second primary winding 17 and filament windings l5 and 16 are mounted on core 32.
  • the filament windings 15 and 5. 16 are wound in a pancake form in this embodiment as shown in FIG. 4, however they maybe woun'd in other geometric forms.
  • All of theab'ove win'din'g's may'ibe be mounted on a common core, and furthermore, asingle primary winding may used. These filament windings are further mounted in a late'ral'spaced relationship to secand primary winding 17. r j
  • Insiilation partitioris 39 attached to both sides of filament windings"to""fiirtherprcivide electrical isolation.
  • Charging winding 33 and bias winding 34 are further mounted on transformer core 32 in a lateral spaced relationship to the primary 17.
  • the charging winding is used to charge a battery (not shown) which provides power for the lamp during the emergency mode.
  • the bias winding is used to hold off the inverter while the normal AC power is available.
  • Insulation partitions 39 are also attached on both sides of the charging, bias, and second primary windings.
  • This insulation is indicated at 36 and is inserted all around the sides 37 of the case 35.
  • This insulation may be made of polyester, however, it may be made of other types of insulation having a relatively low dielectric constant.
  • a plurality of leads 38 is shown extending from housing 35. While only four leads are shown for convenience, there are in this embodiment inreality eleven leads. These leads are connected at one end to various electrical components in housing 35 and the other ends are connected to the lamp L, the battery (not shown) and other connections. These leads should be of a minimum length for performing their electrical connecting functions so as to further minimize stray capacitance.
  • Capacitor 27 of FIGS. 2 and 3 may be housed in enclosure 35 by providing adequate space. This would convertithe ballast from a pure lag circuit to a switch lead circuit.
  • FIG. 5 there is shown a side cut away view of a lighting fixture containing fluorescent lamp having terminals 3 and 4, and an enclosure 35 (which may include the retrofit emergency lighting system and an AC ballast), connected in a channel above the fiuorescentlamp 5.
  • a plurality of leads indicated at 38 areused to connect the'ballast to the terminals of the fluorescent fixture and possibly to a battery for driving the inverter circuit.
  • These leads are shown to be as short as possible to reduce the stray capacitance to ground. That is, they should be made to fit fairly tightly between their connecting point at the lamp terminal, the battery, or other connections and the ballast case.
  • the circuit shown in FIG. 1 has been built and operated with components having the following set of values:
  • Main PrimaryjWinding 9 972 turns, 0.026 inch wire Secondary Winding 10 2238 turns, 0.0113 inch wire Second Primary Winding l7 l5l2 turns, 0.008
  • a ballast apparatus for operating at least one gaseous discharge lamp during normal and emergency modes comprising:
  • ballasting isolation transformer having a main primary winding and a secondary winding, one side of said main primary winding being connected to ground;
  • an inverter circuit connected to said secondary winding for providing operating power during the emergency mode
  • said inverter frequency being in the range of 2.5 KHz and 4.0 KHz for minimizing capacitive leakage current and inductive shunt current; said inverter circuit connected to a DC power source;
  • ballast case a plurality of leads extending from said ballast case, said leads being of minimum length to make their connections so as to provide a substantially low stray capacitance.

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  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
US41565373 1973-11-14 1973-11-14 Retrofit emergency lighting system Expired - Lifetime US3906243A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US41565373 US3906243A (en) 1973-11-14 1973-11-14 Retrofit emergency lighting system
ZA00746374A ZA746374B (en) 1973-11-14 1974-10-07 Retrofit emergency lightning system
GB4885074A GB1481345A (en) 1973-11-14 1974-11-12 Emergency lighting systems
DE19742453496 DE2453496A1 (de) 1973-11-14 1974-11-12 Notbeleuchtungssystem zum nachtraeglichen einbau in vorhandene anlagen
JP13007074A JPS5079974A (OSRAM) 1973-11-14 1974-11-13

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US41565373 US3906243A (en) 1973-11-14 1973-11-14 Retrofit emergency lighting system

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US3906243A true US3906243A (en) 1975-09-16

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US41565373 Expired - Lifetime US3906243A (en) 1973-11-14 1973-11-14 Retrofit emergency lighting system

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US (1) US3906243A (OSRAM)
JP (1) JPS5079974A (OSRAM)
DE (1) DE2453496A1 (OSRAM)
GB (1) GB1481345A (OSRAM)
ZA (1) ZA746374B (OSRAM)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4013993A (en) * 1976-03-22 1977-03-22 Westinghouse Electric Corporation Elevator system
US4042856A (en) * 1975-10-28 1977-08-16 General Electric Company Chopper ballast for gaseous discharge lamps with auxiliary capacitor energy storage
FR2373940A1 (fr) * 1976-12-13 1978-07-07 Legrand Sa Bloc d'eclairage a tube fluorescent, en particulier bloc autonome d'eclairage de securite
US4101806A (en) * 1976-08-26 1978-07-18 General Electric Company Ballast emi and shock hazard reduction
US4161674A (en) * 1977-02-03 1979-07-17 Paul Maurer Overvoltage protected fluorescent tube supply circuit
US6628083B2 (en) 2000-04-28 2003-09-30 Pickering Associates, Inc. Central battery emergency lighting system
EP1341404A3 (en) * 2002-02-28 2004-03-31 ARTEMIDE GROUP S.p.A. Fluorescent lighting fixture

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3636186A1 (de) * 1986-10-24 1988-04-28 Ceag Licht & Strom Schaltungsanordnung fuer eine notbeleuchtung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2356558A (en) * 1939-07-01 1944-08-22 Bahring Herbert Transformer
US3089980A (en) * 1961-06-01 1963-05-14 Gen Electric Ballast apparatus for starting and operating electric discharge lamps
US3116437A (en) * 1962-01-18 1963-12-31 Gen Electric Thermally protected ballast apparatus
US3209241A (en) * 1962-06-13 1965-09-28 Westinghouse Electric Corp Regulating and current limiting transformer system
US3596135A (en) * 1966-11-07 1971-07-27 Andrew Stenger Jr Method and apparatus for detection of breakdown of insulation in electrical equipment
US3684891A (en) * 1970-09-28 1972-08-15 Dual Lite Co Fail-safe solid-state emergency lighting power supply and transfer circuit

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2356558A (en) * 1939-07-01 1944-08-22 Bahring Herbert Transformer
US3089980A (en) * 1961-06-01 1963-05-14 Gen Electric Ballast apparatus for starting and operating electric discharge lamps
US3116437A (en) * 1962-01-18 1963-12-31 Gen Electric Thermally protected ballast apparatus
US3209241A (en) * 1962-06-13 1965-09-28 Westinghouse Electric Corp Regulating and current limiting transformer system
US3596135A (en) * 1966-11-07 1971-07-27 Andrew Stenger Jr Method and apparatus for detection of breakdown of insulation in electrical equipment
US3684891A (en) * 1970-09-28 1972-08-15 Dual Lite Co Fail-safe solid-state emergency lighting power supply and transfer circuit

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4042856A (en) * 1975-10-28 1977-08-16 General Electric Company Chopper ballast for gaseous discharge lamps with auxiliary capacitor energy storage
US4013993A (en) * 1976-03-22 1977-03-22 Westinghouse Electric Corporation Elevator system
US4101806A (en) * 1976-08-26 1978-07-18 General Electric Company Ballast emi and shock hazard reduction
FR2373940A1 (fr) * 1976-12-13 1978-07-07 Legrand Sa Bloc d'eclairage a tube fluorescent, en particulier bloc autonome d'eclairage de securite
US4161674A (en) * 1977-02-03 1979-07-17 Paul Maurer Overvoltage protected fluorescent tube supply circuit
US6628083B2 (en) 2000-04-28 2003-09-30 Pickering Associates, Inc. Central battery emergency lighting system
EP1341404A3 (en) * 2002-02-28 2004-03-31 ARTEMIDE GROUP S.p.A. Fluorescent lighting fixture

Also Published As

Publication number Publication date
ZA746374B (en) 1976-01-28
JPS5079974A (OSRAM) 1975-06-28
DE2453496A1 (de) 1975-05-15
GB1481345A (en) 1977-07-27

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